PBT composite material, preparation method and application thereof

Abstract

The application belongs to the technical field of PBT materials, and particularly discloses a PBT composite material, a preparation method and application thereof. By adding a mold dirt resistance auxiliary agent in the PBT composite material, small molecules generated in the injection molding process of the PBT can be captured, the small molecule content of the system is reduced, the problem of mold dirt is improved, the crystallization temperature is increased to a certain extent, and the material forming is accelerated.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of PBT materials, and particularly relates to a PBT composite material and a preparation method and application thereof. BACKGROUND

[0002] Polybutylene terephthalate (PBT) is a polyester prepared by polycondensation of terephthalic acid and 1,4-butanediol, and is a semi-crystalline thermoplastic polyester with milky white semi-transparency to opacity; PBT has high heat resistance and can work for a long time at a temperature as high as 140 DEG C, has good toughness, fatigue resistance, resistance to organic solvents, self-lubrication and low friction coefficient, and is widely used in the fields of automobiles, mechanical equipment, precision instrument parts, electronic appliances, textiles and the like. However, PBT material itself is prone to degradation under high temperature and high humidity conditions, so it needs to be hydrolysis-resistant modified so as to work for a long time under high temperature and high humidity. Glass fibers are usually added to improve the hydrolysis resistance and creep resistance of PBT material, but the addition of glass fibers will make PBT material more prone to decomposition to form oligomers and small molecules during injection molding, so that the content of small molecules is significantly increased, which will not only cause more residues to appear on the mold during injection molding, resulting in serious mold fouling, and the mold surface needs to be cleaned regularly during continuous processing, causing low production efficiency; and also reduces the molding rate of the material, affects the appearance flatness of the molded surface, and in addition to the cause of mold fouling, the molded parts may have obvious white spots and other defects, which will cause the product to fail to meet the requirements.

[0003] Therefore, there is still a need to continue to develop a PBT material with low mold fouling and fast molding rate during injection molding. SUMMARY

[0004] In view of the problems of easy mold fouling and low molding rate during injection molding of the PBT material involved in the prior art, the application provides a PBT composite material and a preparation method and application thereof.

[0005] To achieve the above-mentioned purpose, the following technical solutions are specifically included:

[0006] On the one hand, the application provides an application of a compound of general formula (I) as a mold fouling-resistant aid in a PBT composite material, and the compound of general formula (I) is as follows:

[0007]

[0008] wherein X1, X2 and X3 are each selected from any one of a hydrogen atom, an alkyl group, an alkoxy group and a halogen.

[0009] The compound of general formula (I) is a compound containing 3-phenyl-2-propenoic acid structure, which can be used as a mold dirt resistance aid in PBT composite material, can react with the hydroxyl group on the small molecule in the system, capture the small molecules generated by PBT, reduce the content of small molecules in the system, improve the mold dirt problem generated in the injection molding process, increase the crystallization temperature of the system, accelerate the molding, and comprehensively realize the low mold dirt and rapid molding of the PBT composite material.

[0010] In the second aspect, the present application provides a PBT composite material, which comprises the following raw material components by weight:

[0011] PBT resin 35-80 parts, glass fiber 9-31 parts, the mold dirt resistance aid 0.4-2.2 parts, and the aid 0.4-1.6 parts.

[0012] Preferably, the compound of general formula (I) includes at least one of 3-phenyl-2-propenoic acid, 3-(4-chlorophenyl)-2-propenoic acid, 3-(3-methylphenyl)-2-propenoic acid, and 3-(2-bromophenyl)-2-propenoic acid.

[0013] Preferably, the PBT resin is 36-78 parts, the glass fiber is 10-30 parts, the mold dirt resistance aid is 0.5-2 parts, and the aid is 0.5-1.5 parts.

[0014] Preferably, the mass percentage content of the PBT resin in the PBT composite material is not less than 30%, preferably not less than 50%, and further preferably not less than 60%.

[0015] Preferably, the intrinsic viscosity of the PBT resin is 0.6-1 dL / g, and further preferably 0.7-0.8 dL / g. The intrinsic viscosity of the PBT resin can be 0.6, 0.7, 0.8, 0.9, 1.0 dL / g, etc., and specific point values between the above point values. Due to the limited space and the consideration of simplicity, the present application will not exhaustively list the specific point values included in the range. The intrinsic viscosity of the PBT resin of the present application is detected by GB / T 14190-2017 method at 25°C. Below the intrinsic viscosity of the above-mentioned PBT resin, the PBT composite material can maintain a low mold dirt quality and a high molding rate during the injection molding process.

[0016] Preferably, the glass fiber is a chopped glass fiber.

[0017] Preferably, the average diameter of the glass fiber is 10-13 μm. The average diameter of the glass fiber can be 10, 11, 12, 13 μm, etc., and specific point values between the above point values. Due to the limited space and the consideration of simplicity, the present application will not exhaustively list the specific point values included in the range.

[0018] The short glass fiber used in the PBT composite material system of the present application can improve the problem of mold fouling during the injection molding process of the material and accelerate the material forming.

[0019] Preferably, the mass of the glass fiber is 15-50% of the mass of the PBT resin, and further preferably the mass of the glass fiber is 25-33% of the mass of the PBT resin.

[0020] The content of the glass fiber is related to the degree of improvement of mold fouling and acceleration of material forming. Within the above content range, it is more advantageous to reduce the mold fouling of the PBT composite material during the injection molding process and to accelerate the forming rate.

[0021] Preferably, the mass of the mold-resistant aid is 0.8-3.5% of the mass of the PBT resin, and further preferably the mass of the mold-resistant aid is 1.5-2.5% of the mass of the PBT resin.

[0022] The mold-resistant aid is a compound containing a 3-phenyl-2 propenoic acid structure. The content of the mold-resistant aid is related to the content of small molecules that can be captured during the injection molding process. Within the above content range of the mold-resistant aid, small molecules generated during the injection molding process can be effectively captured, mold fouling during the injection molding process can be significantly reduced, the crystallization temperature of the material can be increased, and the forming rate of the material can be accelerated. In addition, the mold-resistant aid should not be excessive, otherwise the mold-resistant aid is excessive, and the excess mold-resistant aid acts as a small molecule substance that generates mold fouling, which increases the mass of the mold fouling and reduces the crystallization temperature, resulting in an increase in mold fouling.

[0023] Preferably, the aid includes an antioxidant and a lubricant.

[0024] Further preferably, the antioxidant includes at least one of tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] pentaerythritol ester, pentaerythritol tetra(3-laurylthiopropionate), tris[2.4-di-tert-butylphenyl] phosphite; and the lubricant includes at least one of ethylene bis-stearamide, montan wax, calcium stearate, pentaerythritol tetrastearate.

[0025] In a fourth aspect, the present application provides a preparation method of the PBT composite material, comprising the following steps: mixing PBT resin, mold-resistant aid, aid, and glass fiber, and melting under light, and then extruding and granulating to obtain the PBT composite material.

[0026] In the preparation of the PBT composite material, the present application carries out the preparation of the PBT composite material under light irradiation, the anti-mold additive is first reacted with the terminal hydroxyl group on the PBT to end-cap part of the PBT, and then the carbon-carbon double bond in the acrylic group of the anti-mold additive is polymerized by itself to form a four-membered ring macromolecule, thereby increasing the molecular weight, and the chemical structural formula is as formula II; compared with the structure of the anti-mold additive itself, the molecular weight of formula II is larger, and it is more difficult to precipitate in the injection molding process, so that the problem of aggravating the mold dirt caused by the precipitation of the anti-mold additive can be avoided, and meanwhile, the anti-mold additive consumes part of the terminal hydroxyl group on the PBT in the process of forming the macromolecular capture agent to end-cap part of the PBT, the terminal carboxyl group carried by the capture agent can increase the proportion of the terminal carboxyl group in the system and accelerate the molding of the material.

[0027]

[0028] Preferably, the temperature of the melting is 200-240℃, and the wavelength of the light irradiation is 250-320nm.

[0029] In addition, the present application also provides a PBT composite material and an application thereof in the preparation of electronic appliances, in particular, the application thereof in the preparation of connectors and controllers in the electronic appliance industry.

[0030] Compared with the prior art, the present application has the following beneficial effects: by adding the anti-mold additive into the PBT composite material, the small molecules generated in the injection molding process of the PBT can be captured, the content of the small molecules in the system is reduced, the problem of mold dirt is improved, and the crystallization temperature of the material is increased to some extent, thereby accelerating the molding of the material. DETAILED DESCRIPTION

[0031] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below through specific examples. Unless otherwise specified, the test methods used in the examples and / or comparative examples are all conventional methods; and unless otherwise specified, the materials, reagents and the like used in the present application can be obtained from commercial channels. Unless otherwise specified, the component raw materials used in each example and comparative example of the present application are all the same.

[0032] PBT resin 1: PBT GX110, intrinsic viscosity: 0.6dL / g, Yizheng Chemical Fibre;

[0033] PBT resin 2: PBT GX111, intrinsic viscosity: 0.7dL / g, Yizheng Chemical Fibre;

[0034] PBT resin 3: PBT GX112, intrinsic viscosity: 0.8dL / g, Yizheng Chemical Fibre;

[0035] PBT resin 4: PBT GX121, intrinsic viscosity: 1.0dL / g, Yizheng Chemical Fibre;

[0036] The chemical structure of the mold release agent is shown in the following formula I:

[0037]

[0038] X1, X2, X3 are each selected from any one of hydrogen atom, alkyl, alkoxy, halogen.

[0039] Mold release agent 1: 3-phenyl-2-propenoic acid, Shanghai Jizisheng Biotechnology Co., Ltd.;

[0040] Mold release agent 2: 3-(4-chlorophenyl)-2-propenoic acid, Shanghai Jizisheng Biotechnology Co., Ltd.;

[0041] Mold release agent 3: 3-(3-methylphenyl)-2-propenoic acid, Shanghai Jizisheng Biotechnology Co., Ltd.;

[0042] Mold release agent 4: 3-(2-bromophenyl)-2-propenoic acid, Shanghai Huayuan Century Trading Co., Ltd.;

[0043] Glass fiber 1: diameter 10 μm, ECS10-4.5-534AKF, Jushi Glass Fiber;

[0044] Glass fiber 2: diameter 11 μm, ECS11-4.5-534A, Jushi Glass Fiber;

[0045] Glass fiber 3: diameter 13 μm, ECS13-4.5-534A, Jushi Glass Fiber;

[0046] Antioxidant 1: SONOX 1010, Shandong Sanfeng;

[0047] Antioxidant 2: RIANOX 412S, Tianjin Li'an Long;

[0048] Lubricant: PETS-AP, Fajibase.

[0049] Examples 1-17 and Comparative Examples 1-2

[0050] A method for preparing a PBT composite material, comprising the following steps:

[0051] (1) According to the formulations in Table 1-2, PBT resin, antioxidant and lubricant, mold release agent were weighed respectively, mixed uniformly, and then added to the extruder;

[0052] (2) Then, according to the formulations in Table 1-2, glass fiber was added from the side of the extruder, and was fully melted and mixed uniformly, the melting temperature was 200-240℃, and the light with wavelength of 280 nm was applied in the homogenization section of the extruder, and then the PBT composite material was obtained by extruding and granulating.

[0053] Table 1

[0054]

[0055]

[0056] Table 2

[0057]

[0058] The PBT composite materials prepared in the above examples and comparative examples were subjected to injection mold dirt test and rapid forming effect test:

[0059] (1) Injection mold dirt test: a metal steel sheet was placed at the exhaust port position of the mold, 200 continuous injection molds were injected at 260 DEG C, the mold dirt on the metal sheet was collected and weighed, and the mass difference before and after the metal sheet was used to represent the size of the mold dirt;

[0060] (2) Rapid forming effect: the crystallization temperature of the PBT composite material was used to represent the rapid forming effect, the higher the crystallization temperature of the PBT composite material, the faster the cooling, the shorter the cycle, and the faster the forming rate, wherein the crystallization temperature was tested by differential scanning calorimeter according to ISO11357-2011;

[0061] The test results are shown in Table 3.

[0062] Table 3

[0063]

[0064]

[0065] As can be seen from Example 1 and Comparative Example 1, in the preparation of the PBT composite material, the mold dirt resistant auxiliary agent is added, so that the mold dirt resistant auxiliary agent is polymerized into a macromolecular structure, and in the process of forming the macromolecular structure of the mold dirt resistant auxiliary agent, the terminal hydroxyl groups in the system can be consumed, the proportion of the terminal carboxyl groups is increased, the proportion of the terminal carboxyl groups is increased, which helps to increase the crystallization temperature of the material, shortens the cycle of subsequent injection molding, and accelerates the forming of the material. At the same time, the macromolecular structure of the mold dirt resistant auxiliary agent captures small molecules in the system during the injection molding process, reduces the generation of mold dirt, and the macromolecular structure of the mold dirt resistant auxiliary agent is not easy to precipitate, which will not further aggravate the mold dirt, and the effect of low mold dirt and rapid forming is comprehensively realized.

[0066] From Examples 1-4, it can be seen that the content of small molecule substances in PBT resins with different intrinsic viscosities is different. From the examples, it can be seen that as the intrinsic viscosity of the PBT resin in Examples 2, 1, 3, and 4 increases, the mold deposit mass and the crystallization temperature gradually decrease. The intrinsic viscosity of the PBT resin can be selected to be 0.6-1 L / g, and further preferably 0.7-0.8 L / g. At this time, the PBT composite material maintains a low mold deposit mass and a high molding rate during the injection molding process.

[0067] From Examples 1, 5-7, it can be seen that as the content of glass fibers in Examples 5, 6, 1, and 7 increases, the mold deposit mass first gradually decreases and then significantly increases, and the crystallization temperature gradually increases. When the glass fiber accounts for 15-50% of the mass of the PBT resin, and further preferably 25-33%, the mold deposit content is lower, and the crystallization temperature is also higher at this time.

[0068] From Examples 1 and 8-9, it can be seen that as the diameter of the glass fiber increases, the mold deposit mass gradually increases, and the crystallization temperature gradually decreases. As the diameter of the glass fiber increases, the shear increases, which to some extent increases the mass of the mold deposit. Under the same mass content of the glass fiber, due to the difference in the diameter of the glass fiber, the number of glass fibers in the material is different. Since the glass fiber itself has the effect of heterogeneous nucleation on the PBT resin, the crystallization temperature caused by the glass fiber with a lower diameter is relatively high.

[0069] From Examples 1, 10-12 and Comparative Example 2, it can be seen that as the content of the mold deposit resistant additive in Examples 10, 1, 11, 12, and Comparative Example 2 increases, the mold deposit mass first decreases and then increases, and the crystallization temperature gradually increases. When the content of the mold deposit resistant additive is low, it cannot fully capture the free PBT small molecule substances, resulting in lower mold deposit and crystallization temperature. When the content of the mold deposit resistant additive is too high, the mold deposit resistant additive is excessive, and the excess mold deposit resistant additive acts as a small molecule substance that produces mold deposit, thereby increasing the mold deposit mass and reducing the crystallization temperature, resulting in an increase in mold deposit. Therefore, in the system of the present application, the mass of the mold deposit resistant additive accounts for 0.8-3.5% of the mass of the PBT resin, and further preferably 1.5-2.5%. At this time, the PBT composite material maintains a low mold deposit mass and a high molding rate during the injection molding process.

[0070] From Examples 1 and 13-15, it can be seen that under the same weight parts, the groups in the mold deposit resistant additive are different, and the number of moles of each mold deposit resistant additive in the system is different. The effect of the mold deposit resistant additive with a larger molar mass is smaller than that of the mold deposit resistant additive with a smaller molar mass, thereby causing the mold deposit to be higher to some extent and the crystallization temperature to be lower to some extent.

[0071] From the examples 1 and 16-17, it can be seen that the different contents of the auxiliary agent and PBT result in different contents of the small molecules produced by degradation during the processing, and when the content of the auxiliary agent is too high, the auxiliary agent itself is a small molecule substance, which will result in high mold fouling. Therefore, the components of the PBT composite material within the weight parts required by the present application can make the PBT composite material maintain a low mold fouling quality and a high molding rate during the injection molding process.

[0072] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the essence and scope of the technical solutions of the present application.

Claims

1. The application of a compound of general formula (I) as an antifouling agent in PBT composite materials, characterized in that, The compound of general formula (Ⅰ) is shown below: X1, X2, and X3 are each selected from any one of hydrogen atoms, alkyl groups, alkoxy groups, and halogens.

2. The application as described in claim 1, characterized in that, The compound of general formula (I) includes at least one of 3-phenyl-2-acrylic acid, 3-(4-chlorophenyl)-2-acrylic acid, 3-(3-methylphenyl)-2-acrylic acid, and 3-(2-bromophenyl)-2-acrylic acid.

3. A PBT composite material, characterized in that, The raw material components include the following parts by weight: 35-80 parts of PBT resin, 9-31 parts of glass fiber, 0.4-2.2 parts of the anti-fouling agent as described in claim 1 or 2, and 0.4-1.6 parts of the additive.

4. The PBT composite material as described in claim 3, characterized in that, Includes at least one of the following: (A) The intrinsic viscosity of the PBT resin is 0.6-1 dL / g; (B) The average diameter of the glass fiber is 10-13 μm; (C) The mass of the glass fiber is 15-50% of the mass of the PBT resin.

5. The PBT composite material as described in claim 3, characterized in that, The mass of the anti-fouling agent is 0.8-3.5% of the mass of the PBT resin.

6. The PBT composite material as described in claim 3, characterized in that, The additives include antioxidants and lubricants.

7. The PBT composite material as described in claim 6, characterized in that, The antioxidant includes at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], pentaerythritol tetrakis(3-lauryl thiopropionate), and tris[2,4-di-tert-butylphenyl]phosphite; the lubricant includes at least one of ethylene bis-stearamide, montan wax, calcium stearate, and pentaerythritol tetrastearate.

8. A method for preparing the PBT composite material according to any one of claims 3-7, characterized in that, Includes the following steps: PBT resin, anti-fouling agent, additives and glass fiber are mixed and melted under light, and then extruded and granulated to obtain the PBT composite material.

9. The method for preparing the PBT composite material as described in claim 8, characterized in that, The wavelength of the light is 250-320nm.

10. The application of the PBT composite material according to any one of claims 3-7 in the manufacture of electronic and electrical appliances.

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